Where does “super flu” come from?

super flu (English) comes from English flu, from English influenza, from Italian influenza, from Latin īnfluentia, from Latin īnfluēns, from Latin īnfluō, from Latin īn-, from Latin în — in.

Ancestry of “super flu”, step by step

super flu traces back through two separate lines of ancestry.

via English flu

StepLanguageWordMeaning
1EnglishfluInfluenza; Stomach flu
2EnglishinfluenzaAn acute contagious disease of the upper airways...
3Italianinfluenzainfluence; influenza, flu; third-person singular...
4Latinīnfluentiainfluence
5Latinīnfluēnsflowing into
6Latinīnfluōto flow or run into
7Latinīn-un-, non-, not
8Latinînin, at, on, upon, from (space)
9Latinenlookǃ beholdǃ; reallyǃ?; come onǃ
10Proto-Italicenin
11Proto-Indo-Europeanh₁énin

via English super

StepLanguageWordMeaning
1EnglishsuperOf excellent quality, superfine; better than...
2Englishsuper-egoAlternative spelling of superego
3GermanÜber-Ichsuperego
4GermanIchego, the Ich; self, me, him, etc
5Middle High GermanichI
6Old High GermanihI
7Proto-West GermanicikI
8Proto-Germanic*ek
9Proto-Indo-Europeanéǵh₂I
Every word from Proto-Indo-European h₁én